This is kind of wild, though not unexpected. Google late last month announced it has begun supporting new video tags for Video Sitemaps and mRSS feeds “where [one] can specify metadata specific to television or episodic content.”

The idea, it seems, is that Google wants to gather as much relevant info from publishers — be it bloggers, news outlets, or TV networks proper – about the TV shows and web content people are watching through their site’s embedded video. Perhaps Google at some point wants people to not only tag their video, but document where items of interests happen in the timeline?

No doubt this richness of data will later provide Google with markers that it needs to better catalog video while providing viewers with inline contextual data throughout the timeline (you can see how a “second screen” device or even Google TV could benefit). With all that said, though, the current new tag set is still pretty limited — see here.